Lord Howard of Lympne is a former Leader of the Conservative Party, and sits on the Advisory Board of the Energy and Climate Intelligence Unit.

I briefly attended the United Nations climate change summit in Germany recentlt, at the Government’s invitation. Twenty-five years ago, John Major and I went to the Earth Summit in Rio de Janeiro and signed the United Nations climate change convention for Britain, fulfilling the vision of Margaret Thatcher who, three years previously ,had been the first world leader to say that such a convention was needed.

I could not but be struck last week by the huge changes evident over that quarter of a century. The UK Pavilion, site of many events during the fortnight of the UN talks featuring Britain’s proud track record in climate change, nestled between those of Indonesia and Fiji – countries that one would not automatically think of as having a keen interest in the area. The Chinese and Indian pavilions were substantial. The overwhelming impression was that these countries are not only convinced of the seriousness of climate change, but are keen to play a role in tackling it, and indeed to showcase the role they are playing – in order both to avoid the impacts of rising sea levels and storm surges, but also because of the opportunities that building a low-carbon economy brings.

Such an economy is fertile ground for Britain as we prepare to embark on a new chapter in our history, unencumbered by the European Union. While Germany proclaims itself a “green” leader even as its coal consumption increases, Britain is doing exactly what Sir John and I envisaged 25 years ago – growing our economy while reducing our carbon emissions. In fact, we are not only ahead of most European nations but, more importantly for a post-EU era, we lead the G7 in both per-capita economic growth and per-capita emissions reduction. The average Briton is now 45 per cent richer than at the time of the Rio summit, while we produce one-third less of planet-warming gas.

The importance of this success for a post-Brexit UK is obvious. As progress within the UN climate negotiations demonstrates, other nations with which we will be seeking closer ties are looking to cut their own carbon emissions, and accelerate their transition to clean energy. Britain, and British firms, are good at this. There are now an estimated 400,000 UK jobs in low-carbon goods and services, and the burgeoning global export market can provide many more. For a clear indicator of both UK success and opportunity, look no further than PwC’s annual progress report, which shows that the two countries currently curbing emissions fastest are the UK and China.

Conservatives have been constant leaders on climate change, starting withThatcher’s pioneering speech in 1989 calling for a United Nations treaty. In recent years, however, we have allowed our thunder to be stolen by other parties. It gives me great pleasure, therefore, to observe the renaissance in visible climate change leadership now flowering under Theresa May’s leadership. This was evident at the UN talks, where Claire Perry MP, together with her Canadian counterpart Catherine McKenna, launched a new alliance of 20 nations that will phase out use of coal in the coming years.

The UK’s own target year is 2025, a mere eight years away – and, for those of us who have been ambivalent about renewable energy, it is pleasing to see that we are able to ring in renewable energy and ring out coal-burning, while maintaining one of the most secure electricity systems in the world. The Powering Past Coal Alliance shows Britain at its best – enacting pragmatic world-leading policies at home, and bringing the rest of the world with us.

The transition to a cleaner future offers huge opportunities for UK plc. One in every five electric vehicles sold in Europe is made in Sunderland. London is now the hub for “green” finance, and despite Emmanuel Macron’s attempted seduction it will remain so after Brexit. Just last week, the Queen visited the Siemens factory in Hull to witness the production of enormous wind turbine blades that will soon be shipped out to sea, attached to huge pylons, and provide the power that cooks our Christmas turkeys – power that is now cost-competitive with any other generation technology.

Whether or not you accept the vast and growing pile of scientific reports showing that our carbon emissions are driving climate change, the rest of the world does. Engaging with this, as our ministers did at the UN talks, offers significant diplomatic gains for the UK and commercial opportunities for its businesses. Meanwhile, recent polling by Bright Blue shows that our younger voters are increasingly concerned about climate change and demand our commitment.

There is much more work to do to fulfil Thatcher’s vision of a world where people are secure from the worst impacts of climate change. But as the Paris Agreement shows, there is now real progress. It is doubly pleasing to me that the last 25 years have shown that Sir John and I were entirely correct in our belief that reducing carbon emissions would prove perfectly compatible with economic growth; and this should give Claire Perry and her fellow ministers confidence as they enact new policies for the next 25 years.

In 1989, Thatcher told the UN General Assembly that climate change could only be curbed “through a vast international, co-operative effort.” I am delighted to report that as the UN talks indicate, this effort is well underway, with Britain in the vanguard.